Collapsible dispensing tubes containing fluids have been known in the art for many years. Certain collapsible tubes are used with a nozzle tip of decreasing diameter that is attachable to the outlet port of the collapsible tube, so that the highly viscous material being dispensed from the tube can be presented at a customer-determined width onto the target surface. For a person to use the decreasing diameter nozzle, he must cut the nozzle near its tip at a location along its decreasing diameter that will provide a bead of highly viscous material of desired diameter as the material is being dispensed.
It is frequently desirable to dispense certain highly viscous materials, such as silicone gasket sealant, in a bead having a very narrow line width Collapsible tubes which contain highly viscous materials such as silicone gasket sealant are difficult to use when the person squeezing the tube is using his bare hands to dispense the material in a uniform bead, especially if the line width of the bead is to be narrow. The more narrow the width of the bead, the more force is required to push the material out of the collapsible tube. If the bead is to be of such narrowness as to be useful for many applications, then the force that is required to push the material out of the tube will be so great that the dispensing of the highly viscous material becomes almost uncontrollable, and makes it very likely that the bead produced will not be straight.
An additional problem in dispensing highly viscous material from collapsible tubes is that it is very difficult to squeeze all of the contents from the tube when using only bare hands; in fact, it is virtually impossible. Because of the difficulties in using material-containing collapsible tubes, and because of the popularity of such tubes regardless of the difficulties in their use, the prior art has attempted to solve the above problems in dispensing highly viscous material from such tubes in various ways.
One popular method in the prior art of dispensing material from collapsible tubes (or collapsible bags) is the use of rollers which squeeze the tube from the crimped, closed end toward the open end of the tube, thereby causing such material to be forced out of the tube. Examples of such prior art are U.S. Patent Nos. 1,207,534 (by Gammeter), 2,357,351 (by Oliver), 3,221,940 (by Watson), 3,249,258 (by Kramer), 4,405,062 (by Tschida), and 4,998,645 (by Pearson). Such devices have the general configuration wherein the collapsible tube is placed inside a rigid container, and a portion of the tube is placed between a pair of rollers which are spaced-apart, and parallel to one another. The above patents disclose various methods of either sliding the collapsible tube toward the rollers, or sliding the rollers toward the open end of the collapsible tube, but in all cases, require some type of internal moving parts (the rollers and/or the sliding mechanism) which create a more complex and expensive apparatus than desired.
Another popular method in the prior art of dispensing material from collapsible tubes (or collapsible bags) is the use of either a piston or a plunger to squeeze the tube from the crimped, closed end toward the open end of the tube, thereby causing the material to be forced out of the tube. Examples of such prior art are U.S. Pat. Nos. 1,677,603 (by Steen), 2,772,028 (by Lopez), 2,833,444 (by Sherbondy), 3,308,836 (by Joines), 3,933,273 (by Cox), 4,515,293 (by Hill), 4,711,373 (by Christine), and 5,035,347 (by Trovo). Such devices have the general configuration wherein the collapsible tube is placed inside a rigid container, and a piston or a plunger is pushed against the tube (or collapsible bag), thereby squeezing the tube from the crimped, closed end toward the open end of the tube, causing such material to be forced out of the tube. The above patents all disclose devices which require some type of internal moving parts (i.e., the piston or the plunger, usually having an associated spring of some type), and are unnecessarily complex and expensive.
Another method for dispensing material from collapsible tubes in the prior art is the use of a pressure plate to squeeze the tube, wherein the pressure plate is actuated by a trigger of a dispensing gun. Examples of such prior art are U.S. Pat. Nos. 2,936,097 (by Loria), and 3,481,510 (by Allen). These patents, again, disclose devices which require some type of internal moving parts.
A further method for dispensing material from collapsible tubes in the prior art is the use of a key which is turned, thereby rolling the tube from its crimped, closed end around the key. The act of rolling the tube around the key compresses the tube, and forces its contents to be expressed. Examples of such prior art are U.S. Pat. Nos. 1,166,643 (by Wayne), and 2,551,909 (by Soileau). The apparatus that implements this method is simple; however, the bead produced by turning the key is not precise for the reason that it is difficult to hold a steady aim (for placement of the bead upon the target) while, at the same time, turning the key.
A yet further method for dispensing material from collapsible tubes in the prior art is the use of a twisting cap which, while being turned, twists the closed end of the tube. The act of twisting the tube's closed end, while the open end of the tube is held stationary, forces the tube's contents to be expressed. Examples of such prior art are U.S. Pat. Nos. 1,959,365 (by Jeffreys), and 3,593,885 (by Wiggins, et al.). The apparatus that implements this method also is simple; however, the bead produced by turning the end cap is not precise for the reason that it is difficult to hold a steady aim (for placement of the bead upon the target) while, at the same time, twisting the end cap of the apparatus. From this standpoint, this method is similar to the use of a key to roll up the tube from its closed end, discussed above.
A still further method for dispensing material from collapsible tubes (or collapsible bags) in the prior art is the use of compressed air to apply force to either the sides or the crimped, closed end of the tube (or the closed end of the bag), thereby forcing the tube's (or bag's) contents to be expressed. Examples of such prior art are U.S. Pat. Nos. 2,766,907 (by Wallace), 3,282,473 (by Moore), 3,871,553 (by Steinberg), 3,945,534 (by Ady), 4,909,416 (by Evezich), and 5,012,956 (by Stoody). Devices that implement this method either use the human hand to produce the pressure that collapses the tube, or require a compressed air source for the same purpose. It is obvious that compressed air, rather than hand-squeezing, would be required in order to gain a sufficient mechanical advantage to make it easier to squeeze a tube that had an outlet port of small diameter, in order to produce a bead having a small width.
Another method for dispensing material from collapsible tubes (or collapsible bags) in the prior art is the use of solid plates which apply force to both sides of the tube (or bag), thereby forcing the tube's contents to be expressed. Examples of such prior art are U.S. Pat. Nos. 4,502,613 (by Yamamoto), 4,565,303 (by Gilbertson), and 4,627,554 (by Leibinsohn). The Leibinsohn device consists of two elastic plates (which are flexible yet strong enough to apply force to the collapsible container) that are hinged together, and have a collapsible container filled with liquid that is placed between the elastic plates. The plates can be closed over the collapsible container, thus exerting a continuous force to the container and forcing liquid out of the container. It is specifically designed to dispense an infusion liquid at a substantially constant pressure.
The Yamamoto apparatus includes hinged top and bottom covers that close over the collapsible tube at two slot locations, and which tend to squeeze the contents from the tube due to the force exerted by the narrowed slots against the sides of the tube. Once the covers are closed, a pivotable lever can be rotated to compress a portion of the tube and to lock the tube in place. To dispense further material from the tube, the tube is drawn through the slots in the closed covers, thereby squeezing further contents from the tube, and also tending to rotate the pivotable lever into its unlocked position. Once the tube is properly repositioned, the pivotable lever can be again rotated into its locking position. It is obvious that the operation of drawing the collapsible tube through the slots in the closed covers would be difficult to manually perform, especially in the case of a tube that had an outlet port of small diameter (and thus requires a large effort to squeeze out any material). In addition, the bead produced while attempting to draw the tube through the closed covers' slots would neither be in a straight line nor would have a uniform line width, because the pressure exerted against the tube would be virtually uncontrollable while the tube was being so drawn.
The Gilbertson apparatus consists of a base member and a pivotable, removable cover. The cover is removed in order to insert a collapsible tube into the apparatus, then the cover is returned to its normal position, thereby locking the tube in place between the base and the cover. Once this is accomplished, the base and cover are manually squeezed together, thereby causing the contents of the tube to be expressed. The base and cover engage the tube along a substantial portion of the length of the tube, and tend to collapse the tube progressively from the closed, rearward end toward the open, forward end, thus minimizing the amount of wasted material that remains in the tube.
As can be seen, above, the prior art utilizes devices of relative complexity in order to dispense highly viscous material from collapsible tubes. Only a few of the prior art devices are both simple in construction (having no rollers or pistons, for example), and easy enough to use so that hand-squeezing force alone is sufficient to express the contents of such collapsible tubes.